1. Field of the Invention
An embodiment of the invention relates to an image forming apparatus, a method of controlling an image forming apparatus, and a program for controlling an image forming apparatus. Particularly, the relates to a billing control for an image forming apparatus.
2. Description of the Related Art
In recent years, information tends to be computerized, and image processing apparatuses, such as printers or facsimiles used to output computerized information and scanners used to computerize documents, have become inevitable. In many cases, the image processing apparatus has, for example, an imaging function, an image forming function, and a communication function and is configured as a multifunction peripheral (MFP) capable of being used as a printer, a facsimile, a scanner, and a copying machine.
Among the image processing apparatuses, the printer that is used to output computerized information may provide a usage-based billing service that billing amounts for the number of pages which are printed out. In the usage-based billing service, the following methods have been proposed: a method of calculating the percentage of a color print region and determining a billing amount on the basis of the percentage (for example, see Japanese Patent Application Laid-open No. 2002-91743); and a method of calculating and estimating the amount of toner used and determining a billing amount on the basis of the estimation result (for example, Japanese Patent Application Laid-open No. 2000-19906).
Both the methods disclosed in Japanese Patent Application Laid-open No. 2002-91743 and Japanese Patent Application Laid-open No. 2000-19906 involve, for example, the calculation of the print region or the calculation of the amount of toner used. The calculation process needs to be performed on the basis of the print job after the print job is input to the printer. Therefore, the printer needs to ensure resources also for the calculation process. As a result, the resource for performing the image processing is occupied and the throughput of an image forming/outputting process is reduced. In addition, since it is difficult to accurately calculate the print region or the amount of toner used as described above, the reliability of a billing amount determined on the basis of the calculation result is not sufficiently high.